How to connect multiple RaspberryPi via I2C?

Question

Electronics

For tests I use two RPi3B+ with the latest Raspbian.
As a result, I want to get something like this.

I connected pins 2-3 and 2-5 through 10k resistors on the first raspberry
Connected pins 3,5,9 with pins 3,5,9 of the second raspberry

I2C interface was enabled on both devices in the settings
What to do next? Do I need to somehow initialize the connection?
Tried to display active connections but it shows empty

[email protected]:~ $ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --

Answer 1

What to do next?

Next, you need to find out that there are masters and slaves in I2C and dig somewhere there .